Eastern Tent Caterpillar, Forest Tent Caterpillar and Fall Webworm
EASTERN TENT CATERPILLAR Eastern tent caterpillar, Malacosoma americanum, feeds on cherry, apple, and plum. Full-grown caterpillars are about 1.6 inches long. Coloration varies, but in general they have black heads, and bodies marked with a mid-dorsal white stripe down the length of the back. Blue dots separate successive pairs of yellow lateral stripes. The adult moths are light brown with two diagonal white stripes across the forewings. The caterpillars' silken tents are usually found in tree forks. The larvae lay trails of silk from the communal tent to wherever they are feeding. Long trails of larvae can be seen migrating along the silken path between the tent and leaves. Eggs are laid in masses on twigs. Egg masses can be pruned from twigs during the dormant season and destroyed. Caterpillars can be handpicked from the communal tents. Bacillus thuringiensis (Bt) should be used on flowering trees to control young caterpillars. Bt is not harmful to pollinating bees.
FOREST TENT CATERPILLAR The forest tent caterpillar, Malacosoma disstria, feeds on water tupelo, sweetgum, blackgum, birch, elm, maple, oak and flowering fruit trees. Full-grown caterpillars are about 1.6 inches long with light blue heads and blackish bodies with white hairs. Each segment is marked dorsally with a white keyhole-shaped spot. The adult moths are buff colored, with two darker bands on the forewings. Caterpillars are present in early spring, and upon maturity construct cocoons from folded leaves. The adults emerge in late summer and lay eggs in brown masses that encircle twigs. Eastern tent caterpillar egg masses do not encircle the twigs. The caterpillars make silken tents in host trees. On small trees caterpillars can be handpicked and destroyed. Bt can be sprayed to control young larvae. Older larvae can be controlled with a residual insecticide. One generation is produced per year.
FALL WEB WORM The fall webworm, Hyphantria cunea, is a very common defoliator of pecan, sourwood, and persimmon. The caterpillars construct ugly nests of silk around the leaves on which they feed. The caterpillars can be removed by hand on small trees, but larger orchard trees need to be sprayed using high-pressure equipment.
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